1. Field of the Invention
The present invention relates to an audio processing device that performs audio signal processing to a digital audio signal.
2. Description of the Related Art
There is an audio processing device that performs audio signal processing such as D/A conversion and amplification to a digital audio signal. Some of the audio processing devices output an analog audio signal to multiple speakers including a speaker that is provided at a ceiling. (For example, see JP 2009-077379 A.) In recent years, there are cases where a ceiling reflection type speaker that reproduces an audio toward the ceiling is provided instead of the speaker that is provided at the ceiling because providing the speaker at the ceiling is expensive. The audio that is reproduced by the ceiling reflection type speaker reflects at the ceiling and arrives at a listener.
With a ceiling reflection type speaker, the frequency bands which sound better to the listener via a direct route (e.g., a route via which the audio arrives at the listener directly from the ceiling reflection type speaker) and a reflected route (e.g., a route via which the audio arrives at the listener after being reflected at the ceiling) are different. In the direct route, the frequency band of audio that is not more than a predetermined frequency becomes superior. In the reflected route, the frequency band of audio that is not less than a predetermined frequency becomes superior. Therefore, time lag of route difference between the direct route and the reflected route occurs between the audio of low frequency and the audio of high frequency. For this reason, when the listener listens to the audio that is output from the ceiling reflection type speaker, the listener loses a sense of the localization of the audio output and the relationship with the audio output from the other channels.